Ring binder cover

ABSTRACT

A ring binder cover (4) is composed of a pair of themoplastic sheets (20, 22) superimposed in edge-to-edge relation with a stiffener insert panel (23) disposed therebetween. The insert panel bears two parallel grooves (25, 27) which divide the insert into a spine zone (30) and two cover zones (24, 26). The material of the insert lying at the bottom of the grooves forms a pair of flexible strips (32, 34) which, combined with the adjacent portions of the cover sheets, form hinges between the spine and each cover. The peripheral edge portions (40) of the two thermoplastic sheets are sealed together and provide a sealed envelope for the stiffener insert which defines semi-rigid back and front cover panels of the binder, hingedly connected to a rigid spine. The insert can be provided with insert notches (370, 470, 570) at each end of each flexible strip to reduce outward protuberance of the peripheral edge at the hinge ends. At the mouth of each insert notch, the peripheral edge can carry straight across, or can follow inward toward the insert notch to form a seam notch, or can have a seam area which extends inward toward each insert notch. Another feature which can be incorporated into the ring binder concept of this invention is the idea of a curvable spine. The curvable spine idea involves providing one or more hinge-like spine grooves (641, 642, 643, 644) on the inside surface of the spine portion of the insert between the two hinge grooves. This allows the spine to flatten when the covers are open, but to curve about the longitudinal axis of the spine (concave on the inside and convex on the outside) when the covers are closed.

FIELD OF THE INVENTION

This invention relates to ring binders intended to hold sheets ofmaterial.

BACKGROUND OF THE INVENTION

For many years it has been the practice in the manufacture of ringbinders to fabricate the cover for such binders in a three-plyconstruction. Three rigid or semirigid, rectangular inserts or stiffenerpanels are heat-sealed between two superimposed sheets of thermoplasticmaterial. Of the three stiffener panels generally used, two of themapproximate in size, the back and front panels of the binder. The thirdpanel is a narrower insert strip disposed between the two larger panelto form the back panel or spine of the binder. The inner and outerplastic sheets are fused together or heat-sealed around their peripheraledges. The sheets are also sealed transversely between the adjacent,transverse edges of the cover panel inserts and the back panel inserts.The transverse seals form the hinge areas of the binder. U.S. Pat. No.3,195,924 is typical of this type of binder construction.

There are several significant disadvantages in a conventionalheat-sealed binder cover, particularly along the hinge portions wherethe cover and the spine or backbone of the binder intersect. Along thehinge lines, the outer plastic sheets are fused or heat-sealed togetherand their composite thickness is substantially less than the totalthickness of the two sheets before the heat-sealing operation. Forexample: where the two outer sheets of thermoplastic are each 0,015 inchvinyl, the composite thickness, when fused together, is only about 0,020inch or about 30% less than the total of 0,030 inch where there has beenno heat sealing of the plastic sheets. This thickness reductionsignificantly reduces tensile strength.

In addition, during heat-sealing, the more volatile plasticizers in thevinyl sheet materials are volatilized "off" and the hinge lines tend tobe more brittle than the unfused vinyl. This reduces resistance tocracking failure. Moreover, during the heat-sealing operation, the vinylfilms along the hinge lines are invariably stretched over the edges ofthe chipboard inserts when drawn together for sealing so that theplastic sheet material in these areas becomes thinner (thicknessreduction to 33% to 50% are typical) than the unsealed vinyl and thusmore susceptible to material fatigue failure.

Still another practical problem caused by the shortcomings of theabovedescribed prior art construction might be called spine intrusion.This problem occurs when the binder, filled with pages, is sitting in avertical position (with the spine vertical) for a long period of time.More specifically, the loose leaf mechanism of the binder is riveted tothe spine and loaded with paper. The binder is then placed on a shelf ina vertical position, as normally seen in a book case. The weight of thepaper on the top ring rotates the spine inward or forward until thebottom front corner of the edges of the paper comes to rest on thestorage shelf. This stress on the spine and hinges causes the spine-edgeof the covers to spread outward and the upper part of the spine to moveinward between the covers. This happens over a period of time, whichvaries depending upon the weakness of the hinge, and the weight of thepaper. The end result is that usually the upper one third of the spineis bent inward and the outside of the top of the spine is either flushwith, or inside the upper edges of the front and back covers of theloose leaf binder. This effect detracts from the appearance of thebinder. More importantly, this pulling stress on the hinges frequentlycauses the hinges to tear, thus damaging the binder. These and otherdifficulties experienced with the prior an devices have been obviated ina novel manner by the present invention.

The principal object of this invention is to provide an improved ringbinder construction and method of fabricating the same which overcomethe drawbacks of the prior art construction.

Another object of this invention is to provide an improved ring bindercover having a spine and hinge construction of remarkably enhanceddurability without sacrifice in either the appearance or functionalityof the binder.

A still further object of this invention is the provision of aplastic-sealed binder which has the appearance of the more expensivecase-bound-type binder.

With these and other objects in view, as will be apparent to thoseskilled in the art, the invention resides in the combination of partsset forth in the specification and covered by the claim appended hereto.

SUMMARY OF THE INVENTION

A ring binder cover is composed of a pair of thermoplastic sheetssuperimposed in edge-to-edge relation with a stiffener inert paneldisposed therebetween. The insert panel bears two parallel grooves whichdivide the insert into a spine zone and two cover zones. The material ofthe insert lying at the bottom of the grooves forms a pair of webswhich, combined with the adjacent portions of the cover sheets, formhinges between the spine and each cover. The peripheral edge portions ofthe two thermoplastic sheets are sealed together and provide a sealedenvelope for the stiffener insert which defines semi-rigid back andfront cover panels of the binder, hingedly connected to a rigid spine.

The insert can be provided with insert notches at each end of each webto reduce outward protuberance of the peripheral edge at the hinge ends.At the mouth of each insert notch, the peripheral edge can carrystraight across, or can follow inward toward the insert notch to fore aseam notch, or can have a seam web which extends inward toward eachinert notch.

Another feature which can be incorporated into the ring binder conceptof this invention is the idea of a curvable spine. The curvable spineidea involves providing one or more hinge-like spine grooves on theinside surface of the spine portion of the insert between the two hingegrooves. This allows the spine to flatten when the covers are open, butto curve about the longitudinal axis of the spine (concave on the insideand convex on the outside) when the covers are closed.

BRIEF DESCRIPTIONS OF THE DRAWINGS

The above and other objects and advantages of this invention will bemore readily apparent from a reading of the following description takenin conjunction with the following drawings in which:

FIG. 1 is a perspective view of a ring binder of the type embodying thisinvention,

FIG. 2 is a sectional elevational view on an enlarged scale showing aportion of the binder of FIG. 1,

FIG. 3 is an exploded perspective view showing the components of whichthe ring binder embodying this invention is composed,

FIG. 4 is a diagrammatic elevation view of the hinge action embodied inthe present invention,

FIG. 5 is a diagrammatic elevation view of a prior art plastic hingeaction,

FIG. 6 is a diagrammatic view of the device shown in FIG. 4, but withthe covers closed,

FIG. 7 is a diagrammatic view of the prior art device shown in FIG. 5,but with the covers closed,

FIG. 8 is a diagrammatic sectional view of an insert with unitaryhinges,

FIG. 9 is a diagrammatic sectional view of an insert with a full-facehinge layer,

FIG. 10 is a diagrammatic sectional view of an insert with aseparately-tapered hinge,

FIG. 11 is a cross-sectional view of the peripheral seal of the priorart,

FIG. 12 is a cross-sectional view of the peripheral seal which can beincorporated in the present invention,

FIG. 13 is an elevation view of the outside spine of a binder, withcovers closed, showing protuberances at the upper hinge ends,

FIG. 14 is an elevation view of the outside spine of an embodiment ofthe present invention, with covers closed in which the protuberancesshown in FIG. 13 are eliminated,

FIG. 15 is an elevation view, with partial cut-away, of the outsidespine of art embodiment of the present invention, with covers open, andshowing an insert notch and a seam notch,

FIG. 16 is a sectional view taken along line XVI--XVI of FIG. 15,

FIG. 17 is a sectional view taken along line XVII--XVII of FIG. 18,

FIG. 18 is an elevation view, with partial cut-away, of the outsidespine of an embodiment of the present invention, with covers open, andshowing an insert notch and notchless seam,

FIG. 19 is a sectional view taken along line XIX--XIX of FIG. 20,

FIG. 20 is an elevational view, with partial cut-away, of the outsidespine of an embodiment of the present invention, with cover open, andshowing an insert notch and seam web,

FIG. 21 is a perspective view of a ring binder of the type embodying thecurvable-spine concept of this invention,

FIG. 22 is a sectional elevational view on an enlarged scale showing aportion of the binder of FIG. 21, in its open position,

FIG. 23 is an exploded perspective view showing the components of whichthe ring binder embodying the curvable-spine concept of this inventionis composed,

FIG. 24 is a sectional elevational view on an enlarged scale showing aportion of the binder of FIG. 21, in its closed position,

FIG. 25 is a diagrammatic view of the open position of a hinge in a flatspine embodiment,

FIG. 26 is a diagrammatic view of the closed position of a hinge in aflat spine embodiment,

FIG. 27 is a diagrammatic view of the open position of a hinge in acurvable-spine embodiment, and

FIG. 28 is a diagrammatic view of the closed position of a hinge in acurvable-spine embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring in detail to the drawings, FIG. 1 shows a ring binder 4 of thetype embodying this invention. The ring binder includes from and backcover panels 6 and 8, respectively. The two cover panels are hingedalong transverse hinge lines 10 and 12 to a back panel or the spineportion of the binder, as indicated generally 14. A conventional ringbinder mechanism 16 is affixed to the inner surface of the binder alongits backbone portion.

The binder is composed of two rectangular sheets or films 20 and 22 of asynthetic plastic material which is preferably a thermoplasticheat-sealable or fusible material, such as an ethyl-vinyl-acetatepolymer, a poly-vinyl-chloride polymer, or a polyolefin. The polymersheets 20 and 22 are of sufficient overall size to form the entire innerand outer surface covering of the binder. These sheets may be of anydesirable surface texture and may be of any suitable color to give thebinder its desired appearance.

Referring to FIGS. 2 and 3, disposed between thermoplastic sheets, is asemirigid or form stable, rectangular insert 23. The insert 23 is formedor machined with two parallel grooves 25 and 27 which divide the insertinto three zones. Zones 24 and 26 are dimensioned to be approximatelythe same length and width as the cover panels of the binder. Zone 30 isdimensioned to be approximately the same length and width as the spine14. The insert may be made of any suitable stiffening material, such asclipboard or fiberboard. The stiffening material and, the depth of thegrooves 25 and 27 are selected so that the grooves form stable butflexible hinges.

In fabricating the binder, the cover insert 23, made up of zones 24, 30,and 26, are disposed between the two sheets of the vinyl polymer sheetmaterial 20 and 22 and only the peripheral edges 40 (FIG. 1) of thevinyl sheets are sealed together. In this manner, a large sealed pocketor envelope is formed which encapsulates the insert. It will be notedthat no transverse sealing of the vinyl sheets to each other, is carriedout in the area of the binder backbone at or between the hinges 25 and27 of the cover insert 23. Thus, as best illustrated in FIG.. 2, thethermoplastic sheets or films remain entirely separated from each other(except, of course, at the ends of each hinge) and unfused to each other(except at the hinge ends) in the hinge areas of the binder cover.

Because the space between the sheets 20 and 22 is evacuated, the sheet20 is drawn into the grooves 25 and 27 so to form an attractive hingeinner surfaces. Adhesive between the insert 23 and the sheets 20 and 22bonds the sheets 20 and 22 to the insert 23 and especially to the webs32 and 34, to keep the fabricated structure stable and to cause theinsert 23 and sheets 20 and 22 to cooperate in making the hinges verystrong.

The spine zone 30 includes a pair of upstanding posts, studs or rivets38 which are longitudinally spaced apart to fit through correspondinglyspaced holes 42, 43 and 44 provided through the vinyl sheets and insert,along the centerline thereof. By peening over their inner ends, therivets serve to fasten the base plate of the binder mechanism 16securely against the inner surface of the sheet 20.

The hinges 10 and 12 of the binder are formed by the strong materialremaining at the bottom of each groove 25 and 27. With thisconstruction, there is no thermal sealing or fusion of the thermoplasticsheet material in the hinge areas. The sheets will thus retain theirinherent tear strength and pliability and remain highly resistant toembrittlement and material fatigue in contrast to such tendencies insimilar types of binders which heat seal in the hinge area.

This construction thus has all the advantages of the conventionalthree-ply binder construction with stiffening inserts sealed betweenthermoplastic sheets, but does not suffer the drawbacks of these priorbinder constructions because the hinges are formed of the unit insertmaterial.

The manner which the hinges of the present invention function toeliminate spine intrusion is best shown in FIGS. 4 and 6. FIG. 4 showsthe binder starting to close. Each flexible web 32 and 34 is shownadhesively bound to adjacent portions 31 and 33 of the inner sheet 20,and adjacent portions 35 and 36 in the outer sheet 22. The adjacentportions are not thermally treated and therefore retain their fullthickness, strength and failure resistance. FIG. 6 shows that thestability of the hinge prevents spreading of the front and back coverand thereby prevents the binder contents from pulling the spine inward.FIGS. 5 and 7 show the prior art hinge structure, which, as shown inFIG. 7, allows the covers to spread and the spine to be drawn inward.The Separate insert pieces 51, 52 and 53 are each surrounded by theinner sheet 54 and outer sheet 55. The sheets are heat-sealed betweenthe zones to form hinges 56 and 57.

The unitary hinged insert of the present invention may be formed in manyways. In each case, the hinges are formed by flexible webs which connectthe three insert zones together. FIG. 8 shows a diagrammatic sectionalview of the preferred method in which a sheet of fiber board is milledwith two grooves, preferably rectangular in cross-section. The webs 32and 34 which remain after the milling act as strong hinges. In FIG. 9, avariation is shown in which three separate boards are glued to aflexible backing 126 which acts as the hinge. FIG. 10 shows a variationin which the hinges are formed between three separate plates 224, 225,and 226 using flexible tapes 226 and 227.

The binders which are formed by employing the principles of the presentinvention have a hinge construction which give the exterior of the spineof the binder the look of a more expensive, case-bound product. Thislook of quality can be enhanced by sealing the peripheral edges 40 witha geometry which carries the casebound look to the entire exterior ofthe binder. More specifically, as shown in crosssection in FIG. 11, theconventional peripheral seal has a cross-section which includes an innersealed construction 100, a bead 101 exterior to the inner constriction,and then an outer seam 102. By eliminating the bead and outer seam, andthereby leaving only a single minimal seal, as shown in cross-section inFIG. 12, a case-bound look can be achieved.

The above-described ring binder construction has an aspect which can beundesirable. FIG. 13 shows a view of the outside of the spine, with thebinder covers closed. At each end of the hinges 10 and 12, theperipheral seam 40 tends to compress outward of the end of each hinge 10and 12 to form protuberances 60 and These protuberances are neitherlarge or unsightly. However, they can form points of prematurefriction-induced wear and seam splitting if the binder is frequentlyslid across an abrasive shelf or other surface.

It is desirable to eliminate the protuberances 60 and 61 so that thebinder takes the form shown in FIG. 14. In that embodiment, the spine314, with rivet 338, is shown without protuberances at the ends 358 and359 of hinges 310 and 312. The bottom of the spine would also be free ofprotuberances. This is accomplished as shown in FIG. 15, which is a viewof the spine 314 with the front and rear covers 308 and 306 open. Itshould be understood that FIG. 15 shows the top end of the spine 314,while a mirror image of FIG. 15 exists at the bottom end of the spine314. At each hinge end 358 and 359 (and similarly end 360 and 361 at thebottom of the hinges), seam notches or seam semi-circles 362 (notshown), 363, 364 (outside of view), and 365 (outside of view) are cutout of the seam 340 area. The seam 340 is formed on and follows theperiphery of each of the seam notches. In the preferred embodiment ofthis concept, the hinge ends 358 and 359 (and 360, and 361 at the bottomof the spine) of the hinge web 368 and 369 (not visible) of the insert367 are also cut out to form insert notches or insert semi-circles 370(shown in cut-away 366), 371 (not visible in figure), 372 (outside offigure), and 373 (outside of figure). When the binder is closed, theseam notches 362, 363, 364, and 365, reduce the mount of excess seammaterial. These actions eliminate the accumulation of excess seammaterial at the hinge ends and thereby eliminate the protuberances.

The details of seam notch 363 and insert notch 359 are shown in FIG. 16.The other seam notch-insert notch pairs are substantially identical. Thecross-sectional view in FIG. 16, taken along line XVI--XVI of FIG. 15,cuts through seam notch 363, insert notch 371, and hinge 312. The spine314, the insert notch 371 in the insert 367, and the hinge web 369, canbe seen sealed between the polymeric sheet 320 and 322.

There is a second embodiment of the end-of-the-hinge notch concept whichis described above as the first embodiment of that concept. The secondembodiment of the notch concept is appropriate when it is desired tominimize the protuberance problem described in the first embodiment ofthe notch concept, but when the placement of a notch in the peripheralseam of the polymeric sheets, at the hinge ends, is not acceptable.

The protuberance problem can be very significantly reduced if an insertnotch is provided at each of the four hinge ends of the insert, even ifthe seam notches are not formed in the peripheral seam of the polymericsheets.

This second embodiment of the notch concept is shown in FIG. 17 and 18.Referring to FIG. 18, the insert 467 has an insert notch at each of thefour hinge ends. Notch 470 is visible in FIG. 18, because of cut way466. Notch 471 is not visible in FIG. 18, because it is within thepolymeric sheets 420 (not visible) and 422. The outer notches are notwithin the bounds of FIG; 18, but are simply duplicates of the notchshown. Cross-sectional view line XVII--XVII cuts through notch 471. Theseam 440 carries straight across the top of hinge 412, even where thereis an insert notch 471 beneath the polymeric sheet 422 at the top ofhinge 412.

FIG. 17 is a cross-sectional view of the embodiment shown in FIG. 18,taken along line XVlI--XVII. FIG. 17 shows the notch 471 in stiffener467. The notch 471 is at the upper end of hinge 412. The insert notch471 and the entire stiffener 467 are encased between the polymericsheets 420 and 422 which are sealed together at seam 440. Rather thanfollowing the curve of the notch, as occurs in the first embodiment ofthe notch concept, in the second embodiment of the notch concept, theseam 440 bridges across the mouth or diameter of each insert notch. Whenthe binder is closed, the accumulation of excess seam material at thehinge ends is allowed to retract into and is enveloped by the adjacentinsert notch. This eliminates the protuberances at the hinge ends.

There is a third embodiment of the end-of-the-hinge notch concept whichis described above as the first and second embodiments of that concept.The third embodiment of the notch concept is appropriate when it isdesired to minimize the protuberance problem described in the firstembodiment of the notch concept, but the placement of the firstembodiment's notches in the peripheral seam of the polymeric sheets isnot acceptable, and the second embodiment does not sufficiently reducethe protuberance problem.

The protuberance problem can be very significantly reduced if an insertnotch is provided at each hinge end of the insert, and a sealed web isformed inwardly from the peripheral seam of the polymeric sheets up toor into the mouth of each insert notch.

This third embodiment of the notch concept is shown in FIG. 19 and 20.The insert 567 has an insert at each of the four hinge ends. Notch 570is visible in FIG. 20 because of cut way 566. Notch 571 is not visiblein FIG. 20, because it is within the polymeric sheets 520 (not visible)and 522. The other notches are not within the bounds of FIG. 20, but aresimply duplicates of the notch shown. Cross-sectional view line XIX--XIXcuts through notch 571. The seam 540 carries straight across the top ofhinge 512, even where there is an insert notch 571 beneath the polymericsheet 522 at the top of hinge 512.

FIG. 19 is a cross-sectional view of the embodiment shown in FIG. 20,taken along line XIX--XIX. FIG. 19 shows the notch 571 in stiffener 567.The notch 571 is at the upper end of hinge 512. The notch 571 and theentire stiffener 567 are encased between the polymeric sheets 520 and522 which are sealed together at seam 540. Rather than following thecurve of the notch, as occurs in the first embodiment of the notchconcept or simply bridging the mouth of the insert notch, as occurs inthe second embodiment of the notch concept, in the third embodiment ofthe notch concept, the seam 540 bridges across the mouth or diameter ofeach insert notch with an edge web 573. It should be understood thatcorresponding webs 573 and 575 are positioned at corresponding hingeends.

The edge web 574 is formed by extending the peripheral edge bond, (forexample, 540) between the polymeric sheet 522 and 520 inwardly towardthe insert notches (for example, 571), in a semi-circular shape, to forman edge web bond (for example, 578). The normally very narrow peripheralseam 540 or bond becomes much wider at the critical hinge ends becauseof the presence of the edge webs (for example, 574), and edge web bonds(for example, 578). When the binder is closed, the accumulation ofexcess seam material at the hinge ends is allowed to retract into insertnotch 571 and thereby eliminates the protuberance at the hinge end.

The result of employing the third embodiment is a more durable and moreattractive product. The double thickness bonded edge web provides areinforced corner which has high tensile strength not only parallel tothe seam, but also perpendicular to the seam and plane of the openbinder. The former prevents splitting of the hinge and the latterprevents opening of the seam at the hinge end. The edge web alsoprovides abrasion resistant at the hinge end to prevent wear damage.

Another feature which can be incorporated into the ring binder conceptof this invention is the idea of a curvable spine. The curvable spineidea involves providing one or more hinge-like spine grooves on theinside surface of the spine potion of the insert between the two hingegrooves. This allows the spine to flatten when the covers are open, butto curve about the longitudinal axis of the spine (concave on the insideand convex on the outside) when the covers are closed. The designreduces the angular displacement of the hinges from the open to theclosed position and therefore reduces the wear and increases the usefullife of the hinges and binder. Just as importantly, however, theresulting binder has a very attractive look.

When bound books are prepared at the highest level of the book binder'sart, the resulting books typically have a distinctive curved-spine lookwhen closed. This curved-spine look is so visibly characteristic of finebookbinding that it has come to convey a sense of quality anddesirability in books. It has been found that a seemingly simpleextension of the insert-hinge-groove concept of the present inventioncan result in a ring binder having the curved-spine look of finecase-method book binding.

Referring to FIG. 21, and comparing it to FIG. 1, the binder 604 in FIG.21 is shown to have front and back cover panels 606 and 608,respectively. The two cover panels are hinged along Transverse hingelines 610 and 612 to a back panel or spine potion of the binder, asindicated generally by the numeral 614. A conventional ring bindermechanism 616 is affixed to the inner surface of the binder, preferablyon the back cover panel 608, adjacent the spine 614.

As in the other embodiments of the present invention and as best shownin the exploded view of FIG. 23, the binder 604 is composed of tworectangular polymeric sheets 620 and 622. The sheets are of sufficientsize to form the entire inner and outer covering of the binder 604.Disposed between sheets 620 and 622 is a semirigid rectangular insert623. The insert 623 is formed or machined with two parallel hingegrooves 625 and 627 which divide the insert into three zones. Front zone624 and back zone 626 are dimensioned to be approximately the samelength and width as the cover panels of the binder 604. Spine zone 630is dimensioned to be approximately the same length and width as thespine 614.

The primary unique aspect of this embodiment is the provision of spinegrooves between the hinge grooves 625 and 627. These spine grooves actlike the hinge grooves and allow the spine 614 to transform from a flatconfiguration to a curved configuration in which the inner surface ofthe spine is concave about the longitudinal axis of the spine 614. Thespine grooves are spaced on 1 to 2 cm. centers between the hingegrooves. Thus, in a typical 4.5 cm.-diameter-ring binder, as shown inFIGS. 21, 22, 23, and 24, the hinge grooves would be spaced on 6 cm.centers and four spine grooves (641, 642, 643 and 644) would be evenlyspaced on 1.2 cm. centers between the hinge grooves. The spacing andnumber of spine grooves is selected to result in a smooth curve on theoutside surface of the spine when the binder is closed, as shown inFIGS. 21 and 24. FIG. 24 shows a spine with a pronounced curve about thelongitudinal axis of the spine, when the binder is closed.

It should be noted that, in the preferred embodiment of thiscurvable-spine concept, the ring hardware 616 is mounted, byconventional rivets 638 and holes 632, 633 and 634, to one or the otherof the covers 606 or 608 rather than to the spine area. Although thespine area can be used, attachment to one of the covers, preferably theback cover 608, gives far superior results. This is because the spinecurves smoothly around one side of the rings.

FIGS. 22 and 24 present sectional views along the longitudinal axis ofthe spine. FIG. 22 shows the binder 604 open and FIG. 24 shows thebinder 604 closed. In these views, the binge grooves 625 and 627separate the front cover 606 from the spine 614, and separate the rearcover 608 from the spine 614. The ring hardware 616 is mounted on therear cover 608 adjacent the hinge groove 627. FIG. 24 rather clearlyshows that the angle formed between each of the covers 606 and 608 andthe curved spree 614, when the binder is closed, is larger than is thecase when a flat spine is employed. This larger closed angle reduces therange of angle between the open (180 degrees) (see FIG. 27) to closed(approximately 140 degrees) (see FIG. 28) position. A flat-spined binderhas an open position of 180 degrees (see FIG. 25) and a closed angle of80 to 90 degrees (see FIG. 26).

Although for clarity, FIGS. 22 through 24 do not show the hinge notcheswhich have been described above in connection with other embodiments, itshould be understood that this embodiment could include those hingenotches at the ends of the hinge grooves and/or the spine grooves.

It is obvious that minor changes may be made in the form andconstruction of the invention without departing from the material spiritthereof. It is not, however, desired to confine the invention to theexact form herein shown and described, but it is desired to include allsuch as properly come within the scope claimed.

Having thus disclosed this invention, what is claimed is:
 1. A ringbinder comprising:(a) an insert, said insert having a pair of parallelflexible webs spaced apart a predetermined distance to divide saidinsert into three zones, hingedly connected by said pair of parallelflexible webs, said zones being dimensioned to define a front coverpanel, a back cover panel and a spine panel, each of said webs having afirst end and a second end, and an insert notch at each end, (b) amatching pair of thermoplastic, heat-sealable sheets disposed onopposite sides of said insert and heat-sealed together only about theirperipheral edges, and (c) a ring mechanism fixed to said spine panel. 2.The ring binder as recited in claim 1, wherein the peripheral edges ofthe thermoplastic, heat-sealable sheets have seam notches adjacent eachinsert notch.
 3. The ring binder as recited in claim 1, wherein theperipheral edges of the thermoplastic, heat-sealable sheets have seamwebs which extend inward from the peripheral edges and are adjacent eachinsert notch.
 4. The ring binder as set forth in claim 1, wherein saidinsert comprises a sheet of fiber board milled with two grooves.
 5. Thering binder as set forth in claim 1, wherein said insert comprises threeseparate boards attached to a flexible backing.
 6. The ring binder asset forth in claim 1, wherein said insert comprises a center plate and apair of end plates, the center plate and one of the end plates beinginterconnected by a first flexible tape, and the center plate and theother of the end plates being interconnected by a second flexible tape.7. The ring binder as set forth in claim 1, wherein one of said matchingpair of thermoplastic, heat-sealable sheets is adhesively bonded to theinsert.
 8. The ring binder as set forth in claim 1, wherein both of saidmatching pair of thermoplastic, heat sealable sheets are adhesivelybonded to the insert.
 9. The ring binder as set forth in claim 1,wherein the peripheral edges of said matching pair of thermoplastic,heat-sealable sheets are sealed with a single minimal seam.
 10. A ringbinder comprising:(a) an said insert having a pair of parallel flexiblehinge webs spaced apart a predetermined distance to divide said insertinto three zones, hingedly connected by said pair of parallel flexiblewebs, said zones being dimensioned to define a front cover panel, a backcover panel and a spine panel, and having at least one flexible spineweb parallel to and spaced between said hinge webs, wherein at least oneof said parallel flexible hinge webs has an insert notch, (b) a matchingpair of thermoplastic, heat-sealable sheets disposed on opposite sidesof said insert and heat-sealed together only about their peripheraledges, and (c) a ring mechanism fixed to one of said front cover paneland said back cover panel near the spine thereof, (d) whereby said hingewebs, said spine webs and the unsealed portions of said thermoplastic,heat-sealable sheets disposed on opposite sides of said hinge and spinewebs form flexible hinges, enabling the spine to fold conformingly aboutthe ring mechanism when the binder is closed.